Bit-Interleaved Coded Modulation (BICM) is bandwidth-efficient transmission technology, and is implemented in such a manner that an error-correction coder, a bit-by-bit interleaver and a high-order modulator are combined with one another.
BICM can provide excellent performance using a simple structure because it uses a low-density parity check (LDPC) coder or a Turbo coder as the error-correction coder. Furthermore, BICM can provide high-level flexibility because it can select modulation order and the length and code rate of an error correction code in various forms. Due to these advantages, BICM has been used in broadcasting standards, such as DVB-T2 and DVB-NGH, and has a strong possibility of being used in other next-generation broadcasting systems.
In order to support multiple services simultaneously, multiplexing, which is a process of mixing a plurality of signals, is required. Of multiplexing techniques, currently widely used techniques include Time Division Multiplexing (TDM) adapted to divide and use time resources and Frequency Division Multiplexing (FDM) adapted to divide and use frequency resources. That is, TDM is a method of assigning time segments to respective services, and FDM is a technique for assigning frequency resource segments to respective services and then using them. Recently, there is an urgent need for new multiplexing technology that is applicable to a next generation broadcasting system and provides greater flexibility and performance than TDM and FDM.
The decoding process can be greatly changed according to the time interleaving modes corresponding to the physical layer pipes when one service is transmitted using a plurality of physical layer pipes.